Automobile backstop



June 19, 1928. 3,67%963 I F. P. AHMAN Y AUTOMOBI LE BACKS TOP Filed Aug. 9, 1927 Juucni'ot June 19, 1928. 1,673,963

F. P. AHMAN AUTOMOBILE BACKSTOP' Y 7/ ///%/V7//////////// I 9 v I Kori u Patented June 19, 1928. i UNITED STATES PATENT OFFICE.

FRANKIE. AHMAN, iNOBhOLE, VIRGINIA.

' .aoronronnn neonsror.

.Anplicatlon filed August 9, 195?. $erial No. 211,786.

This invention relates to transmissions means preventing rotation of these shafts in and more particularly to the construction of the opposite direction will. it the gearing i an ordinary gear transmission to enable use arranged to connect the shal'ts .tland 12 so thereof l'or locking a vehicle in which it is that the shaft 11 is' driven forwardly, so ttlilpln 'v'ti(l against drifting movements in prevent driving, of the shaft 11 rearwardly either direction as selected. and it the shaft it is connected to drive rear- A further object of the invention is to wardly, will prevent driving of this shalt produce a device of this character which forwardly. It will alsohe obvious that it will additionally prevent reverse or kickthe clutch elements, generally designated at as Ill ing movements of the engine shaft of the 16 and employed toconnect the clutch shalt vehicle with which it is employed. 15 with. the engine shaft 16, are engaged,

A still :Eurtherobject ol? the. invention is this same means will serve to prevent reto produce a device of this character which verse rotation of the engine shaft.

may he readily embodied in standard trans- In accordance with my'invention, I secure n n'nssion constructions without materially against rotation with relation toone of the altering-the present construction thereof. shalls Hand a ratchet disk 17, thus disk Further object of the invention is to probeing shown in the present instance as seduce a device of this character which is cured to the gear 13 which is fast to the noiseless in its operation and which will he shaft 10. Upon the other of the shafts, 1 7a 99 durable and ellicient in service. rotatahly mount a pawl 18 for coaction with These and other objects I attain by the the ratchet disk 17 and provide this pawl construction shown in the accompanying with friction brake mechanism, generally drawings, wherein for the purpose of illus designated at 19, whereby the pawl may be tration is shown a preferred embodiment of operatively engaged with the shaft 12, so my invention and wherein that it will tend to rotate in the same direc- Figure 1 is a vertical sectional view showtion therewith. In the present instance, the ing apparatus constructed in accordance with gear It is shown as provided with a grooved my invention applied to a transmission; hub 20, within the groove of which are dis Figure 2 is a vertical sectional view posed the sections 21 and 22 of a split and 80 through the transmission; 1 eared collar. Through the ears of the sec Figure 3 is a section on the line 3-3 of tions are loosely extended securing bolts 23,

Figure 2. which provide mountings for springs 24 surlleferrin now more particularly to the rounding the bolts between the of one drawings, t re numerals 10, 11 and 12 desigof the sections and nuts 25 mounted on the on 35 miles respectively, the input, output and bolts, so that the sections will he constantly eounter-sl'ialtof an ordinary gear transmisurged; toward one another to frictionally sion. As is well known to those familiar grip the base of the groove. The section 21 with the art, the input shaft transmits its has the pawl 18 secured thereto. while the energy to the eountenshaft 12 through gears section 22 has a lug 26 project ing outwardly o .13 and M and this power is transmitted to therefrom. The transnrission casing 27 is the output shaft hyshiftahle gearing inprovided with a stop :28 against which this i'luilin reverse'gearing, by means of which log will engage when the collar 19 has retion of rotation of the output shaft ta-red, a distance sullicicnt to properly 'disis reversed from that in which it is'kirdinarengage tlie pawl 18 from the teeth 29 oi the too All ily driven. It will be obvious that ii the ratchet, so as\to prevent too great a separir shaft 11 is connected for reverse movement tion of the-pawl and ralel'iet. and the car tends to move forwardlf, the It will be obvious that when the shafts normal direct-ion or rotation of the shaft 19 are rotating i their normal directions; will be reversed and this will tend to rewhich are indi :atrd iv the arrows of Figo verse the normal direction of movement of ure 2, the frictional grip of the collar 19.

the gear 13 of the input shalt uncl'through upon the huh will cause the pawl to he die-- this shaft the direction of rotation of the engaged from the ratchet, so that there is no clutch shalt 15 with which the shaft 10 is noise in operation. When. however, the dieonuected. Since the dirt tion of rotation rection of rotation is reversed, this frictional 55 of t. :lialls l0 and 12 is normally constant grip will cause the pawl to move inward the and opposed, it will be obvious that any ratchet dish; 1? and to engage against a 

